A Beginner's Guide to D/Conditions and Loops/Simple Branching

Programmers familiar with C, C++ or Java are likely to find this section familiar, and may want to skim or skip it at their discretion.

(the if Conditional) [example: More Complicated Input [a program that asks age and makes a "clever" response] ] import std.c.stdio; import std.stdio;

void main() {

 //Create a variable that can hold an integer
 int age;
 
 // writef doe's not flush on all platforms. If you remove fflush
 // below the text might be written after you entered your number.
 writef("Hello, how old are you? ");
 fflush(stdout);

 // scanf reads in a number. %d tells scanf it is a number and the number
 //   is placed in variable age.
 // The & sign in &age tells the compiler that it is a reference to the
 //   variabel that should be sent. 
 scanf("%d",&age);

 // Print different messages depending on how old the user is.
 if(age < 16) 
 {
   // If age is below 16 you are not allowed to practice car-driving in Sweden
   writefln("You are not old enough to practice car driving!");
 }
 else if (age < 18) /* 16 <= age < 18 */
 {  
   writefln("You may practice if you have a permission, but not drive alone!");
 } 
 else /* You are at least 18 so everything should be alright */
 {
   writefln("You may drive as long as you have a licence!");
 }

}